Convert .ogv (ogg theora) to .avi

The first one uses the subprocess module and you enter the
input and output filenames on the command line.
The second one was my first attempt which uses os.system and raw_input.

#!/usr/bin/python
from subprocess import call
import os
import sys

def usage():
print \
"""Usage:
python program_name input_filename output_filename
python convert_ogg.py input.ogv output.avi
"""

def convert():
mencoder = '/usr/bin/mencoder'
input = sys.argv[1]
arg1 = '-ovc'
arg2 = 'lavc'
arg3 = '-oac'
arg4 = 'mp3lame'
arg5 = '-o'
output = sys.argv[2]
call([mencoder, input, arg1, arg2, arg3, arg4, arg5, output])
if os.path.exists(output):
print '\n\tYour', output, 'was created sucessfully!'
sys.exit()
else:
print '\n\tERROR!'
print 'The', output, 'was NOT created!'

if __name__ == '__main__':
if len(sys.argv) < 3:
usage()
else:
convert()

#!/usr/bin/python
#Filename = ogg_to_avi.py

import os,sys

print '\n\togg theora video to avi video\n'
ogg = raw_input('Enter the ogg file to convert: ')
avi = raw_input('Enter the avi to be created: ')
#os.system("%s %s %s %s %s %s %s %s" % ('mencoder', ogg, '-ovc', 'lavc', '-oac',
# ' mp3lame', '-o', avi))

os.system("mencoder %s -ovc lavc -oac mp3lame -o %s" % (ogg, avi))

if os.path.exists(avi):
print '\n\tYour', avi, 'has been created.\n'
sys.exit()

else:
print 'error, something went wrong!'
sys.exit()